Implementing off-line message scheduling on controller area network (CAN)

The controller area network (CAN) is widely used in a number of industrial applications. We present a method that shows how off-line scheduled messages can be scheduled on a CAN. The paper assumes that a schedule, for a set of tasks transmitting messages on a CAN, has been constructed off-line. We present a method that analyzes the off-line schedule and derives a set of periodic messages with fixed priorities, which can be scheduled on a CAN. Based on the information provided by the off-line schedule, the method derives inequality relations between the priorities of the messages under fixed priority scheduling protocols. In case the priority relations of the messages are not solvable, we split some messages into a number of artifacts, to obtain a new set of messages with consistent priorities. We use integer linear programming to minimize the final number messages.